Method and apparatus for preventing slippage of coil-wound mandrels



F. W. SC HULE ET AL I METHOD AND APPARATUS FOR PREVENTING SLIPPAGE OF COIL WOUND MANDRELS Filed July 1923 Dec. 6, 1927.

' INVENTOR FREDERICK m SCHl/LE CHARLES w. HUNT ATToRm Patented Dec. 6, 1927.

, UNITED STATES 1,651,413 PATENT OFFICE.

FREDERICK WILLIAM SCHULE, OF BLOOMEIELD, AND CHARLES WALLACE HUNT, OF SOUTH ORANGE, NEW JERSEY, ASSIGNORS TO WESTINGHOUSE LAMP COMPANY, A

CORPORATION OF PENNSYLVANIA.

METHOD AND APPARATUS FOR PREVENTING SLIPPAGE F COIL-WOUND MANDRELS.

Application filed July 19,

The present invention relates to a method and apparatus for treating coiled filament wire for use in incandescent electric lamps.

An object of the invention is to rovide a method to prevent the slippage of filament when coiled upon a mandrel.

Another object of the invention is to provide a method for roughening'the surface of a mandrel to prevent the displacement of a coil wound thereon.

Another object of the invention is to provide an apparatus for moving a coiled fila ment continuously through a bath and subsequently through a heated atmosphere.

A further object of the 'invention jis to provide an apparatus for continuously passing a mandrel and filament from a bath into aheated atmosphere and in the provision of means for varying the temperature of the atmosphere. I

A still further object of the invention is to provide an apparatus in which .a filament may be passed continuously through a bath and into a heated atmosphere and in which the rate of movement of the filament may be varied.

- Other objects and advantages will be apparent as the description proceeds.

The manufacture of certain types of concentrated filament incandescent lamps requires that a filamentof helical form be provided. This coiled filament is usually produced by winding wire, such as tungsten wire, upon an iron or steel mandrel. The 'diameter of themandrel is usually about twice the diameter of the filament. Filament of this character is produced by any suitable means, such as for instance on automatic winding machines. As the coil is wound on the mandrel, the mandrel and coil are wound upon a spool or drum. It then becomes necessary to straighten the coiled filamentary body and cut it into sections of different lengths depending upon the voltage of the lamp in which they are to be employed.

After the filament has been cut into sections, the mandrel is dissolved by immersion of the sections in an acid bath. The coils may be left in the acid merely long enough to loosen the coiled sections or they may be left in until the mandrel is entirely dissolved.

I ill e pp ci ted th t fi ment f r a 1923. Serial No. 652,487.

'slip upon the mandrel thus causing a slight variation in the total length of each section.

The present invention contemplates a method for preventing the slippage of the wound Wire upon the mandrel, by treating the exposed surface of the mandrel between the turns of the coils with a substance capable of roughenmg or etching the surface of the mandrel, thus confining the wire to the area between the roughened portions of the mandrel. v A wound mandrel so treated may be cut 1I1l30- equal sections and by reason of the roughened surface of the mandrel between the turns of the coils of wire, the stress upon the wire during the cutting operation is insufficient to disturb the wire and thus the severed sections may be maintained of uniform lengths or accurately cut into lengths of any desired lineal dimension.

A desirable method of roughening the surface of a mandrel between the turns of wire Wound thereon, is to immerse the wound mandrel in an acid bath. Nitric acid has been found to give satisfactory results, al-

though sulphuric acid or chloride of ammonium may be used. a

The wound mandrel may be passed through the bath and suflicient time allowed for the acid to attack the mandrel and roughen the surface thereof, after which it may be cut into sections.

The present invention, however, contemplates the use of the method of roughening the surface of the mandrel in cdoperation with a furnace, which is used to anneal and straighten the filament. When so employed, the bath may be disposed in operative relation to a furnace and the wound mandrel may be passed from the bath directly into. the furnace. A practical advantage is obtained by reason of this association of the the mandrel, in that it quickly dries the acid a tation of a furnace havlng an acid bath as"-" sociated therewith.

Referring to the drawing, a suitable sup porting structure comprising a table 10 having a shelf or platform 11 may be provided. A furnace may be suitably positioned on the platform 11. The furnace may consist of a casing 13 having therein, an alundum tube 14 wound with a nichrorne wire 15. The tube 14 may be positioned axially of the casing 13 and the terminalsof the wire may be connected by conductors 15 and 15 with any suitable source of electrical energy, as for instance the generator 17, a switch 18 being provided to make or break the circuit.

For the purpose of varying the temperature of the furnace a rheostat 19, as indicated, may be provided. Adjacent one end of the. furnace, a container 20 havin a treating liquid 21 may be so disposed t at the wire-wound mandrel or filament mandrel 22 may be fed from a drum or spool 23 L and passed through the liquid 21. The

spool may be suitably supported in a hearing 23. The filament mandrel 22 after passing through the bath 21 may travel through the furnace l2 and may be wound upon a spool 24. Any suitable inert atmospiere may be provided in the furnace and an inlet 25 is provided, through Which it has been found preferable to pass nitrogen.

The spool 24 is rotated to wind the filament mandrel thereon, such rotation being effected by reason of the association of the spool with a motor 26. Intermediate the spool and the motor, suitable speed reduction mechanism may be provided. In the present embodiment of the invention a disc reduction drive 27 is provided, comprising a wheel 28 mounted in a bearing 29 secured to the table 10. The wheel 28 is rotated by frictional engagement with a brush-wheel or disc 31.

The disc 31 is provided with a peripheral recess 32 and is movable longitudinally and rotatable with the shaft 33 of the motor 26. A longitudinal movement of the disc 31 may be had through a splined connection to the shaft 33 in the usual manner. For the pur pose of changing the relative position of the disc 31, a yoke 34 is provided to enter the recess 32 in the disc 31. The yoke may have a nut 35 movable upon a threaded rod 36.

The rod 36 may be suitably supported in bearings 37 and 38. A. movement of the nut, and consequently of the disc 31, may be effected by the rotation of a vertical shaft 39 which projects above the shelf 11, the lower end of the rod having secured thereto, a

beveled gear 41 disposed in mesh with a beveled gear 42, secured to the threaded rod 36. A rotation of the rod 39, by m ans of a hand-wheel 39 will, therefore, vary the speed of the wheel 28. At the opposite side of the bearing 29 and secured in the shaft 40, upon which the wheel 28 is mounted, is a .relatively small sheave 43 which is connected by a belt 44 to a relatively large sheave 45. The sheave 45 is secured to a shaft 46 journaled in a bearing 47 secured to the table 10.

At the opposite side of the bearing 47 is a relatively small sheave 48 which is connected by a belt 49 toa large sheave 51. The sheave 51 may be secured to a shaft 52 journaled in a bearing 53. The shaft 52 may also have secured thereto, a relatively small sheave 54 connected by a belt 55 to a sheave 59 secured to a shaft 57 journaled in a bearing 58, secured to the shelf 11.

The shaft 57 may have a sheave 56 secured thereto, which sheave may be connected by a belt 61 to a sheave 62 secured to a shaft 63, upon which the spool 24 is secured. The sllaft 63 may be suitably secured in a bearing 6 An idler 65 may be provided to guide the filament mandrel from the furnace to the spool 24. It will thus be evident, that upon an operation of the motor, motion will be translated to the spool 24 and thus the filament mandrel may be continuously unwound from the drum 23, passed through the liquid in the container 20, thence through the furnace and wound upon the spool 24.

A variation in the temperature of the furnace may be had by an adjustment of the rheostat 19 and the rate of movement of the filament mandrel through the furnace may be changed by a manipulation of the rod 39 to change the relative position of the disc 31. The container 20 may be of any suitable form the one shown comprising a shallow vessel having a tubular portion 67, in order that the wire may be completely immersed in the bath.

When desirable, the mandrel may be roughened previous to the winding of the coil thereon. This may be accomplished by passing the mandrel through the bath as it enters a machine adapted for winding the coil on the mandrel 1' the wire may be roughened prior to the winding of a coil 1, thereon by directing a discharge of the abrasive material against the wire. After a filament wound mandrel has passed through the furnace and is wound upon the drum, it may be removed and subsequently llli cut into sections by a suitable cutting device. By reason of the roughened surface, the tendency of the coil to slip during the cutting operation is greatly reduced and thus the desired accuracy in the length of the sections is attained.

It will be appreciated that by reason of the above method and apparatus, a mandrel having a coil thereon may be treated in a practical and expeditious manner and that the cutting operation may be performed with a greater degree of accuracy.

Although a preferred method is described and one .form of apparatus shown, it is to be understood that modifications may be made therein without departing from the spirit and scope of the appended claims.

What is claimed is:

1. The method of preventing the relative I movement of a mandrel and a coil for a lamp filament wound thereon which comprises etching the surface of the mandrel between the coils.

2. The method of preventing the relative movement of a mandrel in a coil for a lamp filament Wound thereon which comprises chemically treating the surface of the mandrel to etch the same between the coils.

In testimony whereof, we have hereunto subscribed our names this 18th day of July, 1923.

FREDERICK WILLIAM SCHULE. CHARLES WALLACE HUNT. 

